This invention relates to display systems wherein a functional indicium corresponding to a selected function is lit up to indicate such selection and, more particularly, to an arrangement for minimizing the number of required leads between drive circuitry and the display elements.
There are many applications where a selection and/or display arrangement includes a panel having functional indicia imprinted thereon, which indicia are selectively lit up to visually indicate the functional status of the overall system to which the selection/display arrangement is appended. When designing a display arrangement, a primary consideration is the cost of the arrangement. One of the main contributors to the cost of such an arrangement is the total number of power drivers required for the light emitting elements. A common technique for reducing driver cost is to multiplex the display elements in a matrix array of row and column conductors, with a single display element connected at each intersection of a row conductor and a column conductor. In such an arrangement, the number of drivers can be reduced to at most the sum of the number of column conductors plus the number of row conductors while the total number of display elements is equal to the product of the number of column conductors times the number of row conductors. A major disadvantage with such a technique is the number of leads required to operate a given number of display elements. When utilizing integrated circuit chips for driving such a display, there is a practical limitation to the number of connections that can be made to a given integrated circuit chip.
It is therefore an object of this invention to provide a display system with an array of display elements wherein there is an efficient utilization of leads for controlling a given number of display elements.